The invention relates to a fluid transfer mechanism for picking up, transferring and dispensing fluid volumes and more particularly this invention concerns aspirating a fluid volume in a first position, rotating the aspirated fluid to a second position and dispensing the fluid volume in the second position.
Fluid transfer and dispensing mechanisms each operate to dispense amounts of fluid in a desired location; however, prior art devices do not have the capability to pick up or aspirate a precise fluid quantity in a first position, move the fluid quantity to a second position at a high rate of speed and with a very precise positioning of the fluid pick up and dispensing probe in the vertical and horizontal positions. Further, many of the prior art devices were developed to pump a dedicated fluid through the dispenser, such as reagents in chemical analyzing systems or to pick up multiple volumes in a fluid probe separated by air or other fluids. If the flexibility is desired to pick up and dispense different fluid quantities from different sources and mix them with other fluids then the dedicated or in line systems are not capable of being utilized since they either are physically connected only to one fluid or would run the risk of carry-over and contamination between fluids.
In some chemical analyzing systems sample fluids related to a particular patient are programmed for one or more analytical tests such as measuring the chemical reaction resulting from the addition of one or more reagents from a reagent supply. One disadvantage in prior art devices is caused by dedicated reagent positions and typically a dedicated reagent dispensing mechanism for each position. Generally the array of cuvettes or reaction vessels is segmented or divided into the number of positions required by the dedicated reagent positions. For example, 100 cuvette positions with 10 reagent positions results in samples from only 10 patients being tested in the system without regard to the number of tests conducted on the sample from each patient.
Patient No. 1 might require only one test, but all ten positions have to be allotted for that patient's sample in the device since each of the reagent positions is dedicated. Each of the nine empty positions may not be utilized so that the 100 position machine only is effective as a ten patient or sample machine. If this problem is doubled by including 10 second reagents, then the 100 position machine would be divided in half again such that samples from only five patients could be analyzed on the machine at one time. This results in a great increase in elapsed time for a given through put as well as a corresponding decrease in the efficiency of the system. It would be desirable to provide a fluid transfer mechanism which may pick up, move and dispense samples and reagents from one or more positions to increase the flexibility of the system so that each cuvette may include a sample and reagent fluid without regard to the number of tests or reagents in the system.